Android Chromecast 配套库 - 字幕切换按钮

Question

我正在使用 Companion library 将视频从我的应用投射到 Chromecast。有什么办法可以添加字幕/隐藏式字幕切换按钮，以便用户能够打开和关闭它们吗？

我正在阅读他们的 documentation 我可以看到，如何设置字幕 URL

 MediaTrack englishSubtitle = new MediaTrack.Builder(1 /* ID */,
MediaTrack.TYPE_TEXT)
  .setName("English Subtitle")
  .setSubtype(MediaTrack.SUBTYPE_SUBTITLE)
  .setContentId("https://some-url/caption_en.vtt")
  /* language is required for subtitle type but optional otherwise */
  .setLanguage("en-US")
  .build();

但没有说明我应该在哪里处理显示/隐藏操作。

您对我如何添加切换按钮和处理显示/隐藏操作有什么建议吗？

我正在使用 VideoCastManager，它正在使用铸造库中的 VideoCastControllerActivity。

这是我的CastConfiguration

// Build a CastConfiguration object and initialize VideoCastManager
    CastConfiguration options = new CastConfiguration.Builder(MyAppConfig.CHROMECAST_APP_ID)
            .enableAutoReconnect()
            .enableCaptionManagement()
            .enableDebug()
            .enableLockScreen()
            .enableNotification()
            .enableWifiReconnection()
            .setCastControllerImmersive(true)
            .setLaunchOptions(false, Locale.getDefault())
            .setNextPrevVisibilityPolicy(CastConfiguration.NEXT_PREV_VISIBILITY_POLICY_DISABLED)
            .addNotificationAction(CastConfiguration.NOTIFICATION_ACTION_REWIND, false)
            .addNotificationAction(CastConfiguration.NOTIFICATION_ACTION_PLAY_PAUSE, true)
            .addNotificationAction(CastConfiguration.NOTIFICATION_ACTION_DISCONNECT, true)
            .setForwardStep(10)
            .build();

    // Google Chrome Cast initialization of the VideoCastManager that is a helper class from the CasCompanionLibrary
    // that helps us deal with the flow of communicating with chromecast
    VideoCastManager.
            initialize(this, options)
            .setVolumeStep(MyAppConfig.VOLUME_INCREMENT);

然后我正在创建 MediaInfo

MediaMetadata mediaMetadata = new MediaMetadata(MediaMetadata.MEDIA_TYPE_MOVIE);
                mediaMetadata.addImage(new WebImage(Uri.parse(MyAppConfigBase.IMAGE_API_ENDPOINT + movieVideoItem.getImages().getKeyart())));
                mediaMetadata.addImage(new WebImage(Uri.parse(MyAppConfigBase.IMAGE_API_ENDPOINT + movieVideoItem.getImages().getKeyart())));
                mediaMetadata.putString(MediaMetadata.KEY_TITLE, movieVideoItem.getTitle());
                mediaMetadata.putString(MediaMetadata.KEY_SUBTITLE, movieVideoItem.getDescription());
                mediaMetadata.putString("movie-urls", url);
                mediaMetadata.putString("content-type", movieVideoItem.getContent().getHighRes().getType());

                MediaTrack englishSubtitle = new MediaTrack.Builder(1 /* ID */, MediaTrack.TYPE_TEXT)
                        .setName("English Subtitle")
                        .setSubtype(MediaTrack.SUBTYPE_CAPTIONS)
                        .setContentId(closedCaptionsUrl)
                        /* language is required for subtitle type but optional otherwise */
                        .setLanguage("en-US")
                        .build();

                List tracks = new ArrayList();
                tracks.add(englishSubtitle);

                MediaInfo mediaInfo = new MediaInfo.Builder(url)
                        .setStreamDuration(movieVideoItem.getDuration())
                        .setStreamType(MediaInfo.STREAM_TYPE_NONE)
                        .setContentType(type)
                        .setMetadata(mediaMetadata)
                        .setMediaTracks(tracks)
                        .setCustomData(customData)
                        .build();

Answer 1

您需要执行以下操作：

确保您的 MediaInfo 项目具有曲目信息。
确保在设置中启用了轨道，并在配置 CastVideoManager 时启用对轨道的支持。
在您的 activity 中注册一个 OnTracksSelectedListener 侦听器，这样当曲目发生变化时，您的 activity 就会收到通知。

4.Add 一个按钮到您的 activity，点击按钮后，调用如下方法。

private void showTracksChooserDialog()
        throws TransientNetworkDisconnectionException, NoConnectionException {
    FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
    Fragment prev = getSupportFragmentManager().findFragmentByTag(DIALOG_TAG);
    if (prev != null) {
        transaction.remove(prev);
    }
    transaction.addToBackStack(null);

    // Create and show the dialog.
    TracksChooserDialog dialogFragment = TracksChooserDialog
            .newInstance(mCastManager.getRemoteMediaInformation());
    dialogFragment.show(transaction, DIALOG_TAG);
}

这将打开一个（片段）对话框，显示当前文本和音轨并允许用户 select 一个。当 selected 并在该对话框中按下 Ok 时，将调用您在上一步中注册的监听器，然后您可以在监听器中启用轨道。

确保在离开 activity 时删除侦听器。

Android Chromecast 配套库 - 字幕切换按钮

Android Chromecast Companion Library - subtitle toggle button

android

streaming

video-streaming

chromecast

castcompanionlibrary